Agenda of Water and Sewer Advisory Committee Meeting

BYRON SHIRE COUNCIL

Staff Reports - Infrastructure Services 4.1

Staff Reports - Infrastructure Services

Report No. 4.1 Utilities Operational Plan Report

Directorate: Infrastructure Services

Report Author: Cameron Clark, Manager Works

File No: I2023/1588

Summary:

This report summaries the performance of Utilities Department delivery for August – October 2023

RECOMMENDATION:

That the committee notes the report.

Report

DRINKING WATER QUALITY

In August 2023 there were zero (0) critical limit exceedances at Mullumbimby WTP.

In September 2023 there was one (1) critical limit exceedances at Mullumbimby WTP, as detailed in the table below

In October 2023 there were zero (0) critical limit exceedances at Mullumbimby WTP.

From: WaterOutlook > Reports > Special > MONTHLY UTILITIES REPORTS > UTILITIES REPORT - Mullumbimby Drinking Water Quality

CRITICAL LIMIT EXCEEDANCES Mullumbimby Drinking Water Supply Critical Control Points (CCPs) 12 Months to April 2023
Date Occurred	Description	Description and Cause of Issue	Action Taken to Remedy Situation	Action Taken to Prevent Reoccurrence
5/1/23 to 6/1/23	Turbidity Exceedance ‘ Filter 1 & 2 (3 exceedances)	Rainfall event on the 5 Jan 2023 raised the Turbidity in plant process between 6 and 7 Jan 2023 (Filter 1 exceeded on one day and Filter 2 exceeded on both days, see plots below). The finished water on both days had Turbidity of < 0.75 NTU which is within acceptable limits, therefore no impact on supply.	Jar testing and Chemical dosing corrections undertaken throughout. Treated water returned to < 0.23 NTU by 8 Jan 2023.	Continued monitoring of raw water turbidity and filter turbidity.
11/1/23 – 15/1/23	Chlorine Residual at Left Bank Reservoir = 0.19mg/L	Free Chlorine Residual result during weekly sample collection and testing on 11 Jan 2023 was found to be 0.19mg/L at Left Bank Reservoir outlet. The cause of this issue was the Reservoir filling had been isolated since 6th Jan 2023. During this time of no fresh water entering the Reservoir and the high ambient temperatures the chlorine residual slowly trended lower.	The other Reservoir in Mullumbimby had filled then Left Bank Reservoir inlet valve was returned to normal operations. This happened on 15 Jan 2023. During this fill 44% of the volume was filled with fresh filtered chlorinated water from the water treatment plant. After this Left Bank Reservoir Free Chlorine Residual was sampled as 0.75mg/L on 18 Jan 2023	When Reservoirs are isolated. Check Chlorine trends and if trending downwards dose with sodium hypo to keep level within our set parameters.
14/6/23 & 15/6/23	Turbidity Exceedance ‘ Filter 1 = 0.54 MTU & 0.94 NTU	Inline turbidity Instrument on Filter 1 found to be reading incorrectly on the 14/6/23.	The instrument was calibrated on 15/6/23 and readings returned to within operational limits.	Maintain regular calibration schedule of instruments and continue daily reads.
29/6/23	Chlorine Residual at CCP3 = 0.83mg/L	Issue with dosing system	SCADA alarm alerted operator who was able to rectify in a timely manner.
12/7/23	Chlorine Residual at CCP3 = 0.93mg/L	Low Chlorine reading was due to inline instrument problem. As a safeguard the plant was stopped automatically when the low value was recorded. When the plant was attended, onsite test showed Chlorine reading was 1.55 mg/L free and 1.82 mg/L Total, well within guideline values.	Inline instrument maintenance undertaken to rectify underread.	Continued Maintenance on Inline Instruments and continual monitoring of SCADA alarms. Fail safe Plant stop trigger points in place for Chlorine and Turbidity.
14/9/23	Turbidity Exceedance ‘ Filter 2 = 0.83 NTU	Inline Turbidity Instrument on Filter No 2 found to be reading incorrectly (0.83 NTU) on the 14/9/23. Calibrated on the 15/9/23 and found to be reading correctly again. Finished water on this day 14/9/23 0.08 NTU Turbidity on combined Filters Out.	Continual Monitoring	Continual monitoring & planned maintenance

Public Health Reportable Events

There were no water quality reportable events in August, September or October 2023.

Shire Water Consumption

From: WaterOutlook > Reports > Special > MONTHLY UTILITIES REPORTS > UTILITIES REPORT - Water Usage and STP Inflows Summary

STP INFLOWS

From: WaterOutlook > Reports > Special > MONTHLY UTILITIES REPORTS > UTILITIES REPORT - Water Usage and STP Inflows Summary

STP Performance

There were zero (0) STP licence 100 percentile limit exceedances in August, September or October 2023.

STP 100^th PERCENTILE LICENCE LIMIT EXCEEDENCES (TREATED WATER QUALITY) 12 Months to May 2023
Date Occurred	Description	Description and Cause of Issue	Action Taken to Remedy Situation	Action Taken to Prevent Reoccurrence
Byron Bay STP
		No Exceedances
Bangalow STP
		No Exceedances
Brunswick Valley STP
15/02/23	Faecal Coliform Exceedance ‘EPA 1’ of 3750 cfu /100 ml	Exceedance was caused by a high rainfall event over 14th and 15 th February. Hi inflows resulted in bypass of the UV system.	Outflow was retested until FC had dropped to an acceptable level meeting License). This was achieved by 20/02/2023.	Monitor FC testing results and reduce inflow and infiltration into the system.
Ocean Shores STP
4/1/23	Faecal Coliform Exceedance ‘EPA 3’ of 950 cfu /100 ml	Cleaning of wetlands combined with heavy rainfall caused flow of debris to hinder effectiveness of UV.	Operators cleaned UV and tested FC levels continuously until license compliance achieved.	Ensure regular cleaning of Wetlands channel and cleaning of UV Tubes to prevent recurrence.
15/2/23	Faecal Coliform Exceedance ‘EPA 3’ of 1120 cfu /100 ml	15 February 2023 a high FC count was tested at EPA 3. This was due to a High rainfall event on 14th and 15th February.	Retesting was done until FC count met License. This was achieved by 20/02/23.	Monitor FC results. Reduce Inflow--Infiltration into system.
1/3/23	Faecal Coliform Exceedance ‘EPA 3’ of 4700 cfu /100 ml	Investigation determined that organic material from the wetland cell is washing through the UV during high flow periods.	A resample was conducted on 17/3/2023 and the result came back at 130cfu which is within normal operating range.	UV to be cleaned regularly to limit the organic material building up in the unit also monitoring of the water quality going through the wetland.
15/3/23	Faecal Coliform Exceedance ‘EPA 3’ of 730 cfu /100 ml	Investigation determined that organic material from the wetland cell is washing through the UV during high flow periods.	A resample was conducted on 17/3/2023 and the result came back at 130cfu which is within normal operating range.	UV to be cleaned regularly to limit the organic material building up in the unit also monitoring of the water quality going through the wetland.

EPA Reportable Events

There were zero (0) EPA reportable incidents during August, September or October 2023.

TREATED EFFLUENT & REUSE WATER

MANAGEMENT SYSTEMS

Byron Bay treated effluent water balance

Below is a basic water-balance model of Byron Bay effluent management systems, which include the Byron Bay STP, the Byron Bay Urban Recycled Water Scheme (BBURWS), and the Byron Bay Integrated Water Management Reserve (BBIWMR).

A numerical model has been developed to better understand the water-balance dynamics of the site. It is fed with monitoring data (EPA points, STP site reuse, rainfall). It estimates the evapotranspiration output (i.e. environmental effluent reuse) at the BBIWMR. Remaining knowledge gaps in the model include groundwater infiltration in the BBIWMR. EPA 6 flows will be included in the model once the Additional Flow Path system is commissioned.

Total effluent reuse includes urban reuse (EPA 5 flows), STP site reuse and evapotranspiration at the BBIWMR site.

Updated results from the abovementioned model are shown below:

August / September Key observations:

- Rain appears to be a substantial driver for water flows into and out of the effluent management systems. Rainfall over the winter period (June-August) has reduced compared to previous months.

- During winter, monitored flow data shows a decrease in STP inflows (EPA 2) and effluent discharge to the Union Drain (EPA 4). Urban recycled water demand has increased (EPA 5). Modelled environmental reuse (evapotranspiration) decreased (possibly in response to shorter light periods).

- On average, approx. 22% of STP inflows are reused per day. However, variability is high, with reuse ranging from approx. 5% to 73% per day. This variability is attributed to rainfall, variable climate and seasonal patterns.

- It is estimated that effluent reuse represents 26% (approx. 1ML/day) of ADWF inflows to the STP.

- There is untapped reuse potential at the 24 ha site (approx. 500 kL/day). This system is in the process of being reactivated.

- If 24 ha reuse site is reactivated, it is estimated that reuse could be increased to an average of 39% (approx. 1.5 ML/day) if ADWF inflows to the STP.

October Key observations:

- Tyagarah bushfire impacts:

o Supply to the 24ha irrigation site (EPA3) was activated in October 17^th to reduce impact of bushfire (and subsequent peat fires). A daily average of 1.8 ML has been supplied.

o The increase in reuse at the 24ha has seen a sharp decline in effluent discharge into the drain system (EPA4).

- Rain appears to be a substantial driver for water flows into and out of the effluent management systems.

- 2023, particularly the second half of the year, has seen a decrease in rainfall, triggering an increase in urban reuse demand, and a more stable dry-weather discharge trend into the drainage network (EPA4).

- Since October 2022, an average of 23% of STP inflows are reused per day. However, variability is high, with reuse ranging from approx. 5% to 64% per day. This variability is attributed to rainfall, variable climate and seasonal patterns, which in turn affect demand from urban and environmental uses.

- It is estimated that effluent reuse represents 29% (approx. 1.15 ML/day) of ADWF inflows to the STP.

- There is untapped reuse potential at the 24 ha site (approx. 500 kL/day). This system is in the process of being reactivated.

- If 24 ha reuse site is reactivated, it is estimated that reuse could be increased to an average of 42% (approx. 1.68 ML/day) of ADWF inflows to the STP.

Byron Wetlands Water Quality

The data below shows the assimilative and polishing capacity of Byron Wetlands for August to October 2023.

The assimilative and polishing capacity is demonstrated by the nutrient reduction trend between EPA1 and EPA 4 for nitrogen and phosphorus concentrations as follows:

• Total Nitrogen - an average reduction of between 44-81% is seen between EPA1 and EPA4. This is significantly better than that seen in the literature of around 40-55%

• Total Phosphorus - an average decrease of -16% and 9% is seen between EPA1 and EPA4. The increased phosphorus levels at EPA 4 (Wetland Outlet) occur at the end of October 2023. This reduction in the effectiveness of the wetland in phosphorus removal is undoubtedly the impact of the recent bushfire and associated activity at the Wetlands site.

Wetlands Operation

Water levels in the wetlands have remained lower throughout the BBIWMR due to the sustained low rainfall.

The outlets of Cell F and G have remained closed and minimum flows directed to Cells F and G to sustain the water levels for the DPI Salvinia trial. Further sampling as part of the Salvinia management trial has been conducted. Results of laboratory analysis of Salvinia samples show higher levels of Nitrogen at the top of the Cell. Indicating that the Salvinia is supporting nutrient removal function in the Cells F and G.

Periodically additional tope of flows are released into Cells F and G to support the Jacanas present at the top of Cell H.

Cells D and E have been opened and higher water levels are now evident this has resulted in reestablishment of water lilies in Cell D and high levels of bird activity.

Monthly inspections were not conducted due to fire activity commencing on the weekend of 14/15 October.

Fire has impacted on the Frog and Grass Owl habitat to the west and north of the STP and extensively through the Melaleuca regeneration area (see photos below). There has been significant impact to the effluent irrigation system.

The recycled water was used to assist in fire suppression. Additional recycled water lines were installed to support fire fighting activities in conjunction with NPWS and RFS.

A forest fire with grass and trees

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24ha Melaleuca regeneration area

There was not significant impact of the fire on the treatment wetland cells with fire just entering the western side of Cell H (see photo below).

A dirt path through a forest

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Northern End of Cell H

Further release of weevils in the southern drain was undertaken with Shane Austin and DPI (See photos below).

A person in an orange shirt

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Shane Austin and the weevil release site adjacent to EPA 4

The assessment of the function and condition of the southern drain has been commenced See photos below. Clearing of access to critical infrastructure has been completed by Martin Tolley and Shane Austin. Further clearing of vegetation along the southern drain alignment is required.

Water quality performance of the wetlands has been good buy higher nitrogen levels have been recorded at EPA 1 this results in higher loading of the treatment system.

Works have been undertaken to enhance the flow of water into Cells I and J. Excavation of accumulated materials and installation of crushed rock.

Biosolids Management

Volumes Distributed

The table below shows the total biosolids removed from the STP sites and applied to land for the last 12 months to October 2023. There have been no recent movements due to the current dry weather.

From: WaterOutlook > Reports > Special > MONTHLY UTILITIES REPORTS > UTILITIES REPORT - Biosolids Movements

Biosolids Contamination Grading

The allowable uses for Biosolids are detailed in the following extract from the NSW EPA Guidelines: Use and Disposal of Biosolids Products (2020).

The contamination grading results for each STP for the last 3 months are detailed below:

Recycled Water Management Strategy

Update on project progress:

Cost-benefit assessment of future options for effluent reused is being undertaken.

DEVELOPMENT APPLICATIONS

ET Assessments

The graph below illustrates the ET assessment profile from October 2022 to October 2023. In October 2023, the systems planning team required an average of 55.4 days to complete ET assessments.

Overview

Assessments are being completed based on a priority list sent by planning staff each week.

· 13 ET assessments were finalised this month (October 2023).

· 14 referrals are currently on hold due to requested additional information from planners/applicants.

ASSET MAINTENANCE SYSTEM ROLLOUT

Project Status – Assetic Rollout

1. Utilities are a significant way through the rollout of the new maintenance management software Assetic.

a. Four teams (Water Reticulation, Electrical Maintenance, Operational Treatment and Mechanical Treatment) are now live in this system and using it to manage all planned and reactive maintenance tasks.

b. The Rates team are now using the Assetic maintenance system to manage property meter changes (installs and removals) as well as special meter reads.

c. The next and final team to be brought onto Assetic is the Sewer Operations. This team’s planned maintenance tasks and schedule are currently being reviewed and updated, in conjunction with being developed in Assetic. Training and rollout of final team is planned to be end of November to December 2023.

d. Based on feedback from the Mechanical Treatment team, their Planned Maintenance checklists have been reviewed and amended to capture maintenance data that reflects the Assets more accurately.

2. Monthly reporting is now being developed in two streams:

a. For team leaders, who are managing workloads, personalised dashboards have been created within Assetic to manage their team’s work – for example:

b. For Asset Management purposes high level reports have been developed in Power BI. Currently these reports are in a Power BI desktop report however, these will be published to the IS Utilities Workspace for access via the web. Currently BSC IT team and Assetic are developing the integration to allow a live link to Assetic. The following status reports are a sample of these reports.

Assetic Improvements

The Assetic team are working on improvements to streamline the system for field users from feedback requests. Recent improvements include:

1. Simplification of the meter installation/replacement assessment form for bulk installations. There is now an additional Assessment form and simplified process for these cases.

2. In the field App users had to open an allocated work order to identify which sewer pump station the WO was associated with.

3. Improvements in Search Profiles for dashboards to help team leaders monitor work. This work is ongoing, the team can continue to set up dashboard searches as requested.

4. Overview report of Planned Maintenance report (similar to Water Outlook report). A link to this Power BI report has been sent to team leaders.

5. Addition of Resource Recovery assets. Hence maintenance hours spent by Utilities team on these assets can now be captured.

6. Addition of a virtual asset (ID: 222222222). Hence maintenance hours spent by Utilities team on non-utilities assets not in Assetic can now be captured.

Improvements in the pipeline

1. Plant Diary

There is no facility in Assetic to do a daily diary – we are looking at options to facilitate this.

2. Toolbox meeting records

We currently have this in WaterOutlook – we are looking at options to get this in a more user-friendly format.

PLANNED & REACTIVE ASSET MAINTENANCE

1. From this point forward we are going to report on maintenance status from the Assetic system via Reporting in Power BI. Reports such as these will be available online via the IS Utilities Workspace, in the near future.

2. As we collect more data and the final team comes onboard, we will be able to develop more detailed performance indicators and identify insights. At this stage we are just including some interesting summaries, in future trends will be able to be identified and performance monitored against KPIs.

Maintenance Hours

3. Figure 1 shows the manhours by team for the last 6 months and the breakdown between planned and reactive maintenance as well as time worked on non-Utilities assets. Ultimately, we will be able to show the trend between planned and reactive maintenance over time.

Figure 1 – Planned and Reactive Maintenance Breakdown

Figure 2 –Maintenance Manhours by Asset Class

Figure 3 – Ranked Reactive Maintenance Manhours for Reservoirs since March 2023

From a maintenance management perspective, we have reports set up which show overdue Planned Maintenance tasks by team. (Note: Water Reticulation team has been hit with the mains flushing tasks coming around again).

CAPITAL WORKS

TOUCHSTONE ENEGINEERING - Byron Shire Bioenergy Facility Project

WILLOW AND SPARROW

SPS Renewals for Byron, Mullum, Ocean Shores & Bangalow

SPS	% COMPLETE	PUMPS DELIVERED	SWITCH- BOARD DELIVERED	COMPLETED SCOPE SUMMARY
SPS 1002	10	N/A	Quoted	Cast new switchboard pad (1830x1600x200), install new 3x 63mm electrical conduits and new 16mm mains onto pumps, replace switchboard install 2x gateway for pump mounted VSD. Make good old switchboard plinth and penetrations into well and valve chamber.
SPS 1005	100	N/A	N/A	Remove existing broken sealed surface and re-asphalt access road
SPS 1007	10	N/A	Quoted	Install bypass connection and MH. Remove pumps, Guide rails and lifting chains in preparation for coating, allow for EPOXY time. Remove ladder. Add spindle (SS316) on inlet valve. Replace risers in PE 125 and replace lifting chains in SS. Remove existing switchboard and concrete plinths including combined odour vent pole and plinth. Install new switchboard on new concrete pad (1960x1600x200). 3x63mm conduit 16mm electric main. Penos with 2 parts mega poxy (5-10mm). Replace odour with ground mount McBerns filter, try use same vent pipe. Relocate water service. Fix padlock cover on lid.
SPS 2002	0	N/A	N/A	Replace risers PE125 through to the valve chamber, no need for valves. New Spindle on SS316
SPS 2004	100	N/A	N/A	Replace existing DN150 gate valve in the 2002 rising main on outside of well
SPS 2010	10	N/A	Quoted	Replace risers PE180, DN150 outlet gate valves, check valves, Gibault and flanged spigot. Install new Switchboard pad (1600x1600x200) including 3 x 63mm electrical conduits and penos, install new board facing south. Install new 16mm electric mains to green boy approx. 120m away. Water Service Relocation.
SPS 3004	25	N/A	N/A	Install bypass connection and MH. Remove and reinstate pumps, Guide rails and lifting chains as required for coating. Epoxy coat wet well and cover slab.
SPS 3010	10	N/A	N/A	Replace risers PE125 from elbow on wet well to valve pit, DN150 outlet gate valves, check valves. DN150 inlet gate valve and Spindle to be checked when doing service, relocate water service.
SPS 3017	100	N/A	N/A	Replace inlet gate valve, refurbish inlet pipe penetration
SPS 3021	10	N/A	Quoted	Replace DN125 risers, DN100 outlet gate valves, check valves, DN150 inlet gate valve, replace guide rails and brackets, relocate water service, remove vent pole and replace with McBerns odour filter, remove switchboard plinth and replace switchboard.
SPS 4007	N/A	N/A	N/A	Removed from scope
SPS 5003	N/A	N/A	N/A	Removed from scope
SPS 5014	10	N/A	Quoted	Cast new 600x600x200 switchboard plinth, install new 3x63mm conduits to pump well, removing existing conduits and grout. Possibly remove and make good part of the fence. Install new electrical mains from green boy to board, install new switchboard and commission with electricians.
SPS 5017	10	N/A	Quoted	Replace DN125 risers, DN100 outlet gate valves, check valves and dismantling joints, DN150 inlet gate valve and spindle, remove switchboard plinth and replace switchboard on new elevated hardstand approximately 1m above wet well height. Replace vent pole with odour filter on new slab and run new conduits to suite. Relocate water service.
SPS 5020	10	N/A	N/A	Supply and install 2 x new DN125 PE riser pipes through to the valve chamber, new gate valves and check valves, Gibault and flanged spigots. New gate valve DN150 on incoming gravity sewer. New slab for switchboard (3120x1000x200). Apply bitumen coat on spigot. Remove Ladder.
SPS 5022	10	N/A	Quoted	Supply and install new switchboard conduits 3 x 63mm to new concrete platform. Remove existing switchboard and concrete plinths and install new switchboard on new platforms. Design of new platform to be per previous flood platforms, length 2600 by 1200mm wide. Relocate water service. New Covers, grill and frames sealed for odour control. Modify existing plinth to suit new ground mount odour filter.

Willow and Sparrow - Condition Assessments – FY22/23

The condition assessment of gravity sewer mains and maintenance holes was awarded to Willow and Sparrow (Maintenance holes) and Subsurface Mapping Solutions (Mains). The Maintenance hole condition assessments are underway. The CCTV mains contract was awarded to Subsurface Mapping Solutions and work was completed by June 30. The sewer catchments that fall within this scope are across Bangalow, Byron Bay, Mullumbimby, and Ocean Shores. The indicative budgetary limit of $300,000 has covered the costs for both CCTV assessments and MH visual assessments. Condition assessment reports for mains are complete and reports for MH’s are now being finalised.

Willow and Sparrow - Condition Assessments – FY23/24

The condition assessment of gravity sewer mains and maintenance holes was awarded to Willow and Sparrow (Maintenance holes) and Subsurface Mapping Solutions (Mains). The Maintenance hole condition assessments are underway. The CCTV mains contract was awarded to Subsurface Mapping Solutions and work has commenced. The sewer catchments that fall within this scope are across Brunswick Heads, Suffolk Park, Byron Bay, Mullumbimby, and Ocean Shores. The indicative budgetary limit of $350,000 will cover the costs for both CCTV assessments, MH visual assessments and condition assessment reporting.

Gravity Sewer Mains Capital Works Inventory – FY23/24

Willow and Sparrow has been engaged to collect and collate data for all previously renewed/rectified sewer gravity mains in the Byron Shire. This will update council’s asset management systems and streamline the planning process for future capital works programs. The projected budget is $11,000. This work is nearing completion.

PLANIT CONSULTING

Water Main Replacements – Supply and Installation: Fletcher St, Carlyle St and Bangalow Rd Byron Bay; and Azalea St Mullumbimby

Work accomplished in the period:

· Works along Carlye Street commenced on the 18th of September 2023;

· HDD of Cowper St was completed last week;

· Approximately 220m of pipe has been laid to date;

· Unknown services picked up by contractor onsite (i.e., Redundant 100mm AC main) – The IFC design alignment is currently being investigated to avoid clash;

· The remaining water reticulation line (i.e., Carlyle Street, Cowper Street intersection and Massinger Street roundabout) are planned to be completed November; and

· Planit are acting as Superintendent and working closely with CivilCS (Contractor) to finalise the project for BSC.

Reservoir Roof Replacement Works

Work accomplished in the period:

· No works were undertaken in this period.

· The project is currently in the post completion period.

· Planit are working with the Contractor to close out the remaining minor items.

· Planit are working with Council staff to monitor the works and ensure any defects are rectified by the contractor as required.

Water Reservoir Slope Stability Works – Byron Bay and Ocean Shores

Work accomplished in the period:

· Warner Company commenced retaining wall works in September.

· Remaining retaining wall and perimeter fence replacement works planned for early October.

· Contract close-out and defects liability period to follow.

Warrambool Reservoir – Completed Shotcrete Slope (view from Northern end)

Warrambool Reservoir – Retaining wall works underway along southern boundary.

Byron STP inlet works remediation.

Work accomplished in the period:

• The project is currently in the defect’s liability period.

• Planit are working with Council staff to monitor the works and ensure any defects are rectified by the contractor as required.

Mullumbimby Trunk Water Main (Detailed Design)

Work accomplished in the period:

• Minor design changes have been made at the Azalea Street Reservoir site to have the proposed booster pump station located at the outlet of the Azalea Street Reservoir. This change allows for easier delineation of assets and metering if Rous County Council are to take over ownership of the DN400 trunk main (between the Pacific Motorway & Azalea Street Reservoir) in the future. We note that this was requested by RCC.

o Elite Aqua (booster pump specialist) has been consulted for the provision of booster pump sizing and design at the Azalea Street Reservoir site. They will be assisting the detailed design by providing a peer review and pump selection advice.

• Liaison with Byron Shire Council & NSW Public Works determined that the pipeline crossing of Mullumbimby Creek, which was agreed to be strapped to the existing Azalea Street Bridge structure on the downstream side of the bridge. Planit Consulting and SSE (Salu Structural Engineering) met on site to discuss the available fixture options prior to SSE undertaking their design. The final structural engineering design drawings will form part of the detailed design package.

• Following additional input from Byron Bay Surveying, NSW Public Works, Byron Shire Council and APA Group, minor changes to the proposed trunk main alignment was determined to be necessary to avoid clashes and conflicts. Consequently, additional potholing has been requested from Byron Bay Surveying to further confirm the location and depth of existing services.

• Additional to the above, to avoid the root systems of significant trees on Jubilee Avenue, Planit Consulting amended the design alignment to sit beneath the existing road box and within a school drop off zone at Mullumbimby High. Proposed pipe installation methods for these sections will consist primarily of under boring to avoid major disturbances to traffic and reinstatement activities caused as a result of trenching.

• The ASSMP Report is currently being finalised by ENV Solutions and has a new expected delivery date of Friday the 3rd of November. The ASSMP will show the results of soil sampling at five (5) locations along the proposed trunk main alignment and recommend the treatment of Acid Sulfate Soils in areas of the proposed alignment.

• Whilst undertaking the detailed design, Planit Consulting is marking and quantifying the trees and vegetation that will be affected for use in the basis of the updated Review of Environmental Factors and Biodiversity Assessment.

Additional Flow Path

Work accomplished in the period:

· Project finalised and closed; no updates to provide.

Byron STP Aerator platform upgrade

Work accomplished in the period:

· Project finalised and closed; no updates to provide.

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BYRON SHIRE COUNCIL

Staff Reports - Infrastructure Services 4.2

Report No. 4.2 Ocean Shores STP Transfer to Bruns Valley Workshop Presentation

Directorate: Infrastructure Services

Report Author: Cameron Clark, Manager Works

File No: I2023/1753

Summary:

The purpose of this presentation is to discuss the following in relation to strategic infrastructure planning options for Ocean Shores and Brunswick Valley STP’s.

· Study options

· Discuss decision (MCA) criteria

· Gain committee insights

· Discuss preferred option and;

· Way forward

Background:

At its Ordinary Meeting on 28 October 2021, Byron Sire Council resolved [21-451] to:

· Proceed to detailed design for infrastructure to transfer sewage flows from Ocean Shores STP to Brunswick Valley STP for:

a. All current and projected flows to Ocean Shores STP (for the purpose of temporary closure for repairs and flows more than wet weather capacity), and

b. With facility to continue to discharge an adjustable proportion of the flows to Ocean Shores STP (up to ~100% of current sewage flows) on an ongoing basis.

· Investigate options for upgrades to Ocean Shores STP to rectify its prevailing condition, configuration, and redundancy issues, and to improve its efficiency and reliability. The capacity of the upgraded plant would not be required to be increased through the upgrades and may be marginally reduced where cost effective to do so.

· Investigate options (including options with no Balancing Pond) for upgrades to Brunswick STP to rectify any prevailing issues (particularly in UV disinfection), and as required to accommodate the fraction of loads which cannot be reliably treated at the upgraded Ocean Shores STP.

Report

The OSSTP currently has a number of issues that impact on its safe and reliable operation with a view to protecting the environment and Council staff responsible for running and maintaining the plant.

It is a relatively old plant (~27 years old) and operates under an older environmental licence, which the NSW EPA has flagged is due for updating (most likely before 2029 and with tighter limits on effluent quality).

In particular, the ability of the plant to treat peak wet weather flows of more than three times average dry weather flow (ADWF) (and actually up to ~11 times design ADWF) is severely limited by the process configuration and existing equipment. Components of the plant (including aerator supports, decant mechanism, UV disinfection system, chemical storage and dosing systems, electrical switchgear, control systems, biosolids handling/ dewatering system, sludge lagoons) urgently need attention to avoid the plant potentially failing, either in terms of process treatment capacity or OHS&E requirements (including safety of staff and protection of the environment).

The inability of the plant to adequately treat dry weather flows and loads during peak seasonal periods (e.g., around Christmas/ New Year or Easter holidays) has been demonstrated in recent years (e.g., by effluent ammonia exceeding license requirements for river discharge).

The BVSTP is a newer plant (~12 years old) that still has ‘spare’ dry weather capacity, when comparing theoretical (design) capacity to current dry weather flows. However, it does not have significant spare wet weather capacity. For example, during the recent severe wet weather events in Feb-Mar 2022 when widespread regional flooding occurred, BVSTP reached peak instantaneous flow rates that reached 97% of its design hydraulic capacity (7.1 times ADWF).

The existing clarifiers at the plant are relatively aggressively designed; therefore, their ability to fully treat (process capacity) flows of more than approximately five times ADWF is in doubt, particularly if actual sludge settleability is at the lower end of the likely range (i.e., worse than design values).

Due to intractable constraints around hydraulic design of the existing plant, it is not feasible to only add more clarifiers to increase plant wet weather capacity.

Other components of the plant that need attention to correct existing issues are UV disinfection (failure of equipment with limited spares availability and no longer commercially supported), sludge handling (e.g., lack of redundancy in sludge dewatering and supernatant withdrawal from the aerobic digester), as well as buildings to meet Council’s insurance requirements for safe equipment storage.

Transfer and upgrade options investigated.

Transferring wastewater from Ocean Shores to BVSTP will enable ‘load shedding’ from OSSTP.

Transferring indicatively 21% of ADWF from OSSTP (to BVSTP) will help relieve the dry weather loading at OSSTP, particularly during peak holiday seasons, and reduce the risk of environmental non-compliance.

Given the lack of up-to-date wastewater characterisation and associated modelling of OSSTP, as well as uncertainty over future (new) licence requirements for this plant, further work will be required during concept development to accurately define its ability to treat reduced dry weather flows (after load shedding to BVSTP) and consistently meet environmental requirements.

Based on available information, for this study, that capacity is provisionally estimated to be approximately 1.5 ML/d ADWF or 79% of its nominal capacity based on the most recent capacity assessment and assumed wastewater composition (no data for peak holiday loads).

This aligns with 21% dry weather load shedding estimated to be possible by diverting all flows from sewage pump station (SPS) 5004 to BVSTP, via a modification/ extension of its rising main.

It is estimated that full diversion of SPS5004 will divert up to approximately 30% of peak wet weather flows. In this ‘transitional’ scenario (until the ultimate fate of OSSTP is decided), OSSTP will then typically only treat flows from SPS5009 i.e., peak wet weather flows up to approximately 175 L/s (instead of 236 L/s currently), or approximately eight times its original nominal ADWF (instead of nearly 11 times ADWF currently).

To some extent, this will ease the hydraulic bottlenecks in the plant (e.g., the frequency and duration of periods when the intermittent aeration and decanting process stops functioning, thereby interrupting full treatment).

Diverting approximately 21% of OSSTP dry weather flows to BVSTP (i.e., approximately 0.4 ML/d) will increase ADWF at BVSTP from around 1.76 ML/d (based on flow projections that underpinned this study1) to around 2.2 ML/d, or just under 60% of its original design ADWF.

However, diversion of up to approximately 61 L/s of peak wet weather flow from OSSTP to BVSTP will push the combined peak wet weather flow at BVSTP to more than its current hydraulic capacity for incoming raw wastewater (limited to 314 L/s, and currently operating very close to that during major wet weather events).

Given the hydraulic and design constraints at BVSTP, to make the diversion of flows from OSSTP possible whilst deferring a major plant upgrade that would increase capacity, a wet weather storage facility (or ‘balancing pond’) for raw wastewater is required at BVSTP.

Whilst there is some level of risk associated with building and operating an open wet weather storage facility (e.g., increased odour; increased traffic movements or dust during construction; increased maintenance), those risks are considered manageable at this site. When it is not in use, the design operational objective will be to maintain the storage facility empty and nominally dry. The design will enable it to be emptied to mitigate odour.

The facility will be used primarily for storing dilute raw wastewater during wet weather, followed by its contents being pumped back for mainstream treatment within approximately ten days or less, after influent flow rates have subsided.

Only on rare occasions (or emergencies e.g., to carry out essential plant maintenance for which process treatment shutdowns are necessary) will the wet weather storage facility be used to store raw wastewater under dry weather conditions. Raw wastewater diverted to the facility will in any case be screened, to mitigate debris littering and accumulating within it (e.g., posing associated risks to wildlife).

Having the wastewater transfer and storage facilities will give Council significant operational benefits (‘future proofing’) in being able to manage dry and wet weather flows more effectively across the two sites, particularly in the face of increased inflow-infiltration and flood risks associated with climate change. The storage facility design will need to consider projections of future flood levels associated with a rise in sea-level (river levels) and peak wet weather events.

The proposed approach for partial diversion of wastewater from Ocean Shores to BVSTP postpones for Council the decision around the ultimate fate of OSSTP and its possible closure, whilst making full use of the remaining life of the existing assets at that plant.

The timing of OSSTP potential closure and ultimate full transfer to BVSTP, or the alternative (i.e., full upgrade of OSSTP, whilst retaining the capacity for partial transfer of flows/ load shedding to BVSTP) can be decided later. Given the age of the plant, the timing will depend heavily on the ability of the existing OSSTP to continue to operate reliably and achieve required environmental standards (anticipated new license) to the satisfaction of the EPA.

Ultimately, if Council decides in future to close OSSTP, then full transfer of flows to BVSTP will require completion of the transfer facility (i.e., a new transfer pump station at or near OSSTP, pumping via an additional pipeline of larger diameter, via the same easement that proposed for SPS 5004 diversion in the transitional scenario – see above).

It will also require completion of the full upgrade of BVSTP, with the wet weather storage facility (already built and operated for the transitional period) then serving as a useful back-up to full treatment capacity (process and hydraulic), for emergency use and mitigation of potentially deteriorated wet weather flow incursion to the ageing sewer catchments.

Alternatively, if Council decides to retain and fully upgrade OSSTP in future, then the transfer pipeline constructed for the transitional scenario could either be retained for operational flexibility to manage raw wastewater flows and loads between the two plants into the future or be repurposed as a treated effluent/ recycled water main linking the two sites.

The options outlined above have been built into alternative pathways within adaptive plans developed as part of this study (refer table below). The option recommended for implementation was designated ‘Option 4-R’ and aligns with a very similar option (Option 4) originally recommended in the preceding Feasibility Study (GHD, 2016) for this project.

The nuances between Option 4-R and the original Option 4 relate to assumptions made in respect of BVSTP hydraulic and process configuration for partial vs. full process upgrades (i.e., plant capacity duplication), to accommodate the transfer from Ocean Shores.

Implementing Option 4-R in the short to medium term does not preclude future pathway options (e.g., ultimate full transfer and full upgrade of BVSTP vs. ultimate full upgrade of OSSTP), if required. However, Option 4-R has the advantage of the lowest capital cost and lowest NPV of all the options considered.

The minor upgrade of OSSTP potentially offers a long-term pathway to retain both STPs (with load shedding from Oceans Shores to BVSTP), and remain within the capacity envelope of both plants, subject to OSSTP performance in future being satisfactory and sufficient to achieve future EPA license requirements.

In the Multi-Criteria assessment, Option 4-R ranked the highest of all options considered in this study, and was not sensitive to criteria weightings, in the range tested. Hybrid options around Option 4-R were considered.

These involved reduced scope for the minimum upgrade of OSSTP (i.e., confining the scope to only those items most critical in the short to medium term, to keep OSSTP operational, in an effort to reduce capital costs). However, these options pose increased risks (around technical operation/ maintenance and resilience) associated with running an old plant and meeting regulations, including new EPA license requirements.

Those risks will most likely bring forward the date at which OSSTP must be either fully upgraded or closed (i.e., necessitating full transfer and upgrade at BVSTP).

The risks were factored in the scoring for cost criteria (adding capital and hence increasing NPV) and non-cost criteria in the MCA and led to these options ranking lower than Option 4-R, the preferred option. Some of the Option 4-R ‘hybrid’ options also scored very close to the Base Case (i.e., immediate, full upgrade of OSSTP, with no wastewater transfer and no upgrade of BVSTP, and were sensitive to criteria weightings.

This suggests that careful, more detailed assessment would be necessary before recommending any of these options as alternatives to the preferred option.

Cost summary for options considered in this study, based on median capital costs estimates

Scoring and Ranking Results from Multi-Criteria Assessment

Pipeline route

Council obtained an easement in 2012 for the proposed transfer pipeline. The easement passes through Cape Byron Marine Park, Coastal Wetlands and sclerophyll forests and would require extensive vegetation clearing and approval requirements, therefore is not currently preferred.

Preliminary biodiversity assessments investigated the potential impacts of different pipeline transfer routes to identify which of those route options would best achieve the objective of avoiding and minimising impacts to biodiversity values in the locality.

A preferred sewer rising main route has been identified which minimises biodiversity impacts. This route utilises parts of the existing pipeline easement as well as an electricity easement, cleared areas, requires little to no clearing of shrubs or trees and would not contribute to fragmentation of habitat within the locality.

All other routes investigated would require clearing of high environmental value vegetation and subsequently create cleared corridors and fragmentation of habitat. Vegetation potentially impacted through other routes would include estuarine vegetation communities, floodplain forests and wet sclerophyll forests containing good quality Koala habitat. The preferred route (refer figure below) has been chosen to avoid and minimise impacts on the biodiversity values of the proposal area.

Future stages of this project will identify preferred construction methods based on a range of considerations including biodiversity impacts. Additional investigation is likely to be required to determine if any Aboriginal objects are present along the rising main route. It is also recommended that the expansion of BVSTP avoids an existing registered potential archaeological deposit to the south of the existing STP.

Minor upgrades to the OSSTP undertaken within the existing operation footprint are unlikely to significantly impact on terrestrial biodiversity. The major upgrade of the OSSTP would require expansion to the east of the current footprint and into vegetation analogous with Coastal Swamp Forests, which is of significant value and is potential habitat for numerous threatened flora and fauna species. The vegetation within the potential expansion area is homogonous in both age and diversity and is unlikely to be avoided during a major upgrade.

The area identified south and west of the BVSTP is predominantly cleared land, dominated by exotic pasture with only some native ground layer wetland vegetation interspersed along the drainage line and lowest lying areas of the site.

Native wetland vegetation extent and condition is likely to fluctuate depending on seasonal and climatic variations, however, is generally in poor to very poor condition. In the absence of mid and upper storey vegetation layers, the site provides only marginal habitat for threatened species, and predominantly fauna classes such as amphibians.

Based on initial preliminary surveys, it is considered unlikely that the area will provide potential habitat for threatened flora species. The expansion of BVSTP would result in significantly less biodiversity impacts than the OSSTP expansion and would be consistent with the ‘avoid and minimise’ objective.

There are issues/ considerations common to all upgrade options which could be managed effectively using standard mitigation measures, (e.g. ASS, noise, water quality). Cultural heritage values exist throughout the project area and measures can be developed to avoid Aboriginal objects for most (if not all) of the project area. Considering the options and potential issues, the key determining factors are the terrestrial and aquatic biodiversity within the project area. Therefore, the selection of treatment plant site upgrade and preferred pipeline route is mainly dictated by the biodiversity protection objective.

The rising main along Route A, a BVSTP upgrade and a minor upgrade to OSSTP are all permissible without development consent. These activities would be assessed under Part 5 of the Environmental Planning and Assessment Act, 1979 and would require a Review of Environmental Factors (REF).

The recommended options are expected to trigger the Biodiversity Offsets Scheme under the Biodiversity Conservation Act 2016 and require a Biodiversity Development Assessment Report (BDAR) to accompany the REF.

If Aboriginal objects are found and the pipeline route cannot be re-designed to avoid the site an Aboriginal heritage impact permit (AHIP) would be required for permission to harm Aboriginal objects. BSC would be the proponent and determining authority for the project.

Recommended Biodiversity Assessment Method (BAM) surveys were undertaken in late summer 2022/23 and early autumn 2023 in preparation for a BDAR. Surveys evolved with changing considerations, with access to the two largest properties being denied by the landowners after the commencement of this survey work.

This significantly impacted survey design and delivery considerably and adaptations were required. This access constraint impacted the completeness and efficiency of the surveys undertaken to date and additional surveys are still likely to be required.

The surveys undertaken were able to target most of the highly relevant species in line with their respective survey month requirements. However, access constraints impacted surveys targeting some of the better condition habitat within the proposal footprint and adds limitations and caveats to the surveys undertaken.

Preferred pipeline route and original easement

RECOMMENDATION:

That the Committee: -

1. Notes the presentation; -

2. Recommends that:-.

a) Council notify the NSW EPA in response to their letter requesting Councils strategic direction being - Option 4R - Partial transfer to BVSTP, with WWS & Retain OSSTP (capacity limited, with load shedding and a wet weather storage).

b) Council staff start project initiation stage for Option 4R - Partial transfer to BVSTP, with WWS & Retain OSSTP (capacity limited, with load shedding and wet weather storage).

Attachments:

1 OS-BV sewage transfer and treatment, E2023/117217 , page 58 ⇩

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Venue	Conference Room, Station Street, Mullumbimby
Date	Thursday, 16 November 2023
Time	9.00am

Committee Report Tracking Summary: Condition 9. Additional Load at Byron STP	Current Approved ET	Difference (ET)
30 January 2020	2,408	-
30 July 2020	2,478	70
29 October 2020	2,508	30
18 February 2021	2,738	230
29 April 2021	2,749	11
19 August 2021	2,683	(66)
21 October 2021	2,727	44
18 March 2022	2,791	64
18 August 2022	2,810	19
16 November 2023	2,871	61

CSP Objective	CSP Strategy	DP Action	Code	OP Activity
5: Connected Infrastructure	5.5: Provide continuous and sustainable water and sewerage management	5.5.2: Wastewater management - Manage effluent in an ecologically sustainable way that ensures public health and protects and enhances the natural environment	5.5.2.6	Undertake wastewater network inflow and infiltration reduction initiatives at Mullumbimby
5: Connected Infrastructure	5.5: Provide continuous and sustainable water and sewerage management	5.5.2: Wastewater management - Manage effluent in an ecologically sustainable way that ensures public health and protects and enhances the natural environment	5.5.2.8	Undertake wastewater network inflow and infiltration reduction initiatives (except Mullumbimby which has dedicated program of work)